Steam-boiler



L. F. HOFFMAN AND W. J. UNKEL.

STEAM BOILER.

APPLICATION FILED AUG.26. 1919.

. 1 327 159; Patehted Jan.'6,'1920.

UNITED STATES PATENT oEEIoE.

LOUIS F. HOFFMAN AND WINNIE J. UN KEL, 0F KINDER, LOUISIANA.

STEAM-BOILER.

Specification of Letters Patent.

Patented Jan. 6, 1920.

Application filed August 26, 1919. I Serial No. 319,890.

To all whom it may concern:

Be it known that we, LOUIS F. HOFFMAN and IVINNIE J. UNKEL, citlzens of the Unlted States, residing at Kinder, in the parish of Allen and State of Louisiana, have in vented certain new and useful Improvements in Steam-Boilers, of which the following is a specification.

This invention relates to steam boilers in which compressed air is heated and mixed with the steam to supply motive power for driving engines or for other purposes; and it consists in the novel construction and combination of the parts hereinafter fully described and claimed.

In the drawings, a longitudinal section of a boiler is shown provided with means for introducing compressed air according to this invention.

The boiler may be of any approved construction, and in the example shown the shell 2 of the boiler is arranged horizontally, and is provided with return fire-tubes 3 which are connected to a smoke-box I having a chimney or smoke-stack 5. The boiler fire grate or furnace is arranged underneath the shell, and is of any approved construction.

An air pump 6 of any approved kind is provided, and is preferably driven by steam and air from the said boiler. The air pump forces a supply of compressed air into an air reservoir or air drum 7 in which it is kept at a predetermined pressure, as inclicated by a pressure-gage 8.

The air outlet pipe 9 from the air drum is provided with a regulating valve 10, and excessive pressure in the air drum is prevented by a suitable safety-valve 12. A check valve 14 is also provided in the outlet pipe 9 to prevent water from passing from the boiler into the air drum.

A pipe 15 is arranged inside the water space of the boiler at the bottom part of the shell, and below and between the fire-tubes. This pipe 15 is provided with a plurality of folds or convolutions and it is connected at one end to the air pipe 9. The other end of the pipe 15 is closed by a plug 16, and a multiplicity of small perforations 17 is provided in its sides along its folds or convolutions. The convolutions or folds are preferably arranged in a vertical plane, and the air pipe is connected to the top convolution of the series, from which the perforations 17 may be omitted.

The compressed air from the air drum is heated in the convolutions of the pipe 15, and is discharged into the water through the small perforations. The air improves the circulation of the water in the boiler, facilitates the separation of the steam from the water, and prevents the adhesion of scale to the tubes and shell. The compressed air rises with the steam through the water, and forms with the steam a mixture which can advantageously be used for driving engines and for other purposes.

What we claim is:

The combination, with a steam boiler, of a perforated pipe arranged in the water space of the boiler, said pipe being provided with a series of folds or convolutions arranged in a vertical plane, a reservoir for compressed air, an outlet pipe provided with a regulating valve and a check valve and connecting the air reservoir with the top convolution of the said perforated pipe, and a pump for forcing compressed air into the reservoir.

In testimony whereof we affix our signatures.

Louis F. HOFFMAN. WINNIE J. UNKEL. 

